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Should you be worried about an asteroid impact? Live Conversation with Phil Plait - Join now!

This Conversation will open on December 1st, 1 pm EST.

Asteroids are the solar system's leftovers: chunks of rock and metal ranging in size from too small to see to hundreds of kilometers across. They pose a great threat to life on Earth - just ask a dinosaur, which you can't, because an asteroid wiped them out - but they're also a great opportunity for science and possibly even for our economy. What do we know about them, what don't we know, what do we wish we knew? Now you can find out: Dr. Philip Plait, astronomer and science evangelizer, will answer your asteroidal questions live on December 1 from 1-2 pm. EST.

Watch his talk: " How to defend Earth from asteroids" http://www.ted.com/talks/phil_plait_how_to_defend_earth_from_asteroids.html

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Topics: Live Conversation asteroid astronomy dinosaurs science
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Closing Statement from Phil Plait

First, thank you to the folks at TED and of course to everyone who came to ask questions! That was exhausting, but fun. I don't think I've ever typed faster in my life. :)

If there's one thing I want you to take away from this topic, it's this: the threat from comets and asteroids is small - very small; after all, we're still here! - but real. If we wait long enough (decades? centuries?) then some rock big enough to do damage will come along. We have to take this threat seriously, and the good news is lots of people are.

We are scanning the sky looking for these potential impactors, we have more telescopes coming online in the next few years to make the search deeper and more efficient, and there are lots of ideas on what to do should we see such a rock headed our way. Odds are we'll have a few years notice for any big threats. My hope is that by talking about this, by spreading the word and getting more folks interested in it, we'll have an even better chance of fighting back if and when that time comes.

Thanks again!

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  • Alexzander Samuelsson

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    Dec 1 2011: Thanks Phil for doing this. It was an unexpected surprise and very delightful. Keep up the good work!

  • Lorna Francis

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    Dec 1 2011: Hi Phil, wondering if you could expand on mining asteroids as you mentioned in your talk, how this might be done and what kind of materials might be acquired? What asteroids would be best to mine?

  • R Kew

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    Dec 1 2011: Thanks for the chat Phil, I love the badastronomy blog and your general take on all things universal...Cheers!!!

  • Richard Vahrman

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    Dec 1 2011: Interested in the idea of a tug moving an object into orbit. Any chance that it could be tried out on another planet e.g. Mars until we got it right
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      Phil Plait

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      Dec 1 2011: No, Mars is way too big for that! But it would be a great idea to test it on a rock we know is already safe, and measure how much we move it. That way, when one comes along we need to deal with, we're ready.
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    Iddo Geva

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    Dec 1 2011: Two part question, first off does the sun have an effect on asteroids in terms of minor pushes in orbit and how can we tell if so and secondly, what about the so called dark asteroids, ones that can't be seen visually, how do we go about detecting them.
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      Phil Plait

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      Dec 1 2011: Actually, yes. If the asteroid spins, the heating of the Sun can act like a very low thrust rocket, called the YORP effect (you can look this up). That's very slow, acting over years,so it's something to keep track of but is not a major problem.

      Dark asteroids are a problem; ones that are so black they are difficult to detect. However, they still glow in the infrared, so we need telescopes that detect IR light (like WISE did) to find those. it's makes things more difficult, but we do have the means to find them!
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    Christophe Cop 500+

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    Dec 1 2011: Are there any bets for or against Apophis (striking earth) to be made somewhere?

    Just interested, as the ETA of the rock happens to be on my birthday ;-)
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      Phil Plait

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      Dec 1 2011: Heh. Well, the latest odds of it passing through the keyhole and then hitting us in 2036 are roughly a million to one. I don't know if Vegas is taking bets though. :)

  • David Rodriguez

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    Dec 1 2011: If we did decide to make an asteroid moon (I humbly submit the name Moon 2: Electric boogaloo), what sort of horrible tide effects could we expect?
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      Phil Plait

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      Dec 1 2011: Probably nothing to worry about. Even a rock several miles wide would have negligible effect on the Earth.

  • tony duncan

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    Dec 1 2011: Ah related to my previous question. Obviously a body 2x or more larger than earth would have to be moved MUCH farther away from earth, so as not to affect our orbit, and we wouldn't want it hitting any other planets or worse the Sun.
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      Phil Plait

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      Dec 1 2011: True, but the Earth is 13,000 km across and we know there's nothing out there anywhere near that big; we're talking rocks only a few km across or smaller. So that's not really a concern.

  • Shawn Marsh

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    Dec 1 2011: Assuming we can develop technology to feasibly predict the path of and accurately redirect asteroids, should we be concerned that a "fine-tuned" method such as the gravity pull might instead be used to redirect an asteroid INTO the keyhole. Ie as a WMD or a threat of a weapon? Should we be worried about Dr. Evil?
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      Phil Plait

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      Dec 1 2011: I do think about that sometimes, but in reality the mission would be a huge team effort, so it would be hard for some nefarious evil mastermind to do that. But it's possible. My bigger worry is, what if some country contributes to the mission, and it's their part that fails, making the asteroid land on their enemy's country? It's pretty far fetched, but just another thing governments have to work out: liability.
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    Chung Truong Thanh 50+

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    Dec 1 2011: Assuming 3 years from now on, a really really big asteroid will hit the earth. In the movie, the US government will pay all for the effort to save the earth :). Thanks.

    What do you think in real? Will the financial argue will kill us all?
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      Phil Plait

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      Dec 1 2011: This is a real problem! If it's a global effect, then everyone wants to get involved, and not everyone gets along so well. :) There are groups trying to figure this out, like the B612 Foundation I mention in the talk. I don't know how that will work out. Lots of missions have international cooperation, so the more we do that, the better groundwork we lay to when we really NEED to do it. :)

  • Alexzander Samuelsson

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    Dec 1 2011: Is there a way for chemists to help out in the field of asteroid deflection? If so, how?
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      Phil Plait

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      Dec 1 2011: That's an interesting questions. We need to understand the composition of asteroids and comets to know how best to deflect them, so chemistry is important. I don't know how to get involved with this field specifically for a chemist, but I know lots of geochemists work for NASA. Poke around the NASA website and see what's there (also Universities which work with NASA).

  • Adam Wong

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    Dec 1 2011: Just for kicks, how difficult would it be to put Apophis in a stable orbit around Earth? I've always wanted another Moon.
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      Phil Plait

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      Dec 1 2011: I actually am not sure. I suspect it could be done with a space tug like I talked about, but it would take far longer than just nudging it into a non-impacting orbit. Still, ion engines have lots of time and if your'e clever - and rocket scientists are - they could use the gravity of the Earth and Moon to help as well. We;ve done that to get probes to other planets, so we know how already!

  • eli jarra

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    Dec 1 2011: I would like to join a team that analyzes data from night sky to detect NEO's. Do you think there will be programs available similar to Seti@home that would allow us to do just that? Would be nice to have more interaction from the end-user than just computer cpu usage.
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    Iddo Geva

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    Dec 1 2011: Another question that comes to mind is the idea of parking an asteroid in orbit, wouldn't something the size and mass of Apophis play with tidal events on the planet?
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      Phil Plait

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      Dec 1 2011: basically, no: it takes a big object to have tidal effects, and even one a few miles across would have a negligible effect. And if it did, we'd make sure it was in a higher orbit. :)

  • R Kew

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    Dec 1 2011: I figure that the actual composition of any particular asteroid, eg mass/density in addition to the size/volume would be something to consider as far as the effectiveness of which possible diversion, destruction or other techniques that would be proposed to avoid collision? How would the composition effect choices made about dealing with the possibility of impact...
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      Phil Plait

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      Dec 1 2011: That's true. Some asteroids are fragile, and if you whack them hard enough they might fly apart. That would be bad; then you're dealing with shrapnel. Others are metal and would have no problem absorbing the impact. The bottom line is, we need to know more about asteroids in general so that when we do see one with our number on it, we'll understand how best to deal with it.

      • R Kew

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        Dec 1 2011: Exactly... As even with NEO detection abilities increased 10 fold it would seem that given the massive distances involved we would need a fairly long, as in many, many year warning to be able to have any chance of making any difference given current technologies... Not to say that further research in to methods of detection and defense of our planet isn't needed but more to make folks realize that this is an important subject, sort of a cosmic game of pool, lawn bowling or curling that with out some serious thought towards "training" we have a low chance of winning with out committing to further study...
        Maybe instead of spending all the $$$ funding & fighting wars against each other we should focus on the much "bigger picture" eh?

  • Jason Greenwood

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    Dec 1 2011: The Russians and the Chinese are independently pursuing He-3 lunar mining and fusion. If He-3 can be taken advantage of, the country to do so will be the sole superpower. Why isn't the US? Any other thoughts on He-3 fusion?
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      Phil Plait

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      Dec 1 2011: I have mixed feelings about this. We don't actually *have* an He-3 reactor yet; all these ideas are theoretical on how to make one. So this idea of mining the moon for HE-3 seems a bit premature to me. I'm no expert though. I'd rather we were exploring the Moon for all the other reasons, and then hey, if someone invents He3 fusion reactors, we're already in place to take advantage of them!

  • Alexzander Samuelsson

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    Dec 1 2011: Is there a possibility to create inexpensive probes that can be spread around the inner solar system to scan for large NEO's, or is that just science fiction?
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      Phil Plait

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      Dec 1 2011: The best way to look for them for now is just using good old telescopes! Some on the ground, some in space; that way we can scan the whole sky and see what's out there. There are so many that it wouldn't work to try to create probes to look for them directly; you just do that once a dangerous one is found.

  • tony duncan

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    Dec 1 2011: I just saw Melancholia last night. SO it is quite a co-incidence noticing this on facebook today.
    So how would we go about preventing an impact from a body much larger than ours. In the movie they have it moving at 40,000mph. How much lead time would we have detecting a stray planet. At that speed (assuming it was steady) it would be about 3 years/billion miles. Would we be able to detect it 30 years before impact? and would we have any chance of mounting any sort of technologic plan that would move it sufficiently.
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      Phil Plait

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      Dec 1 2011: I haven't' seen the movie yet (I want to!) but the good news is that planets are big and bright, so we've found all the big ones close in to the Sun - and by close in, I mean farther out than Neptune. Even at the speed you mention, something coming in from farther away from that would take decades or centuries to get here. We don't think there are any other big planets beyond Neptune - there might be, but they'd be REALLY far off - so we're OK for the next few millennia at least. :)

  • Adam Wong

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    Dec 1 2011: I've heard that the best option is to launch a vehicle that would impart gravitational force on the approaching asteroid... Would the probe need to be extra massive? Would it need to orbit the asteroid several times in order to change its trajectory significantly? And how fast could a mission be organized, compared to the amount of warning we have?
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      Phil Plait

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      Dec 1 2011: The more massive the impactor, the harder it hits (think American football players). The best thing would be a direct impact trajectory: aim at the rock, and bang! to orbit it you have to slow WAY down, so that makes the impact much less effective.

      As far as how long it would take, I answered that earlier, so it's on this Q&A somewhere; scroll down to see it!

  • Jake Barlow

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    Dec 1 2011: no question for now, just thanks for doing this. I love your blog!

  • Alain Giaume

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    Dec 1 2011: Hi Phil,
    What is the time of detection before impact nowadays?
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      Phil Plait

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      Dec 1 2011: Well, that depends on what you mean. A big rock, capable of doing global or regional damage, might be seen years in advance. Something small, like 100 meters in size, might not be seen literally until we see the flash in the sky. We have seen small rocks before they hit us, like 2008 TC3, which was 2 meters across and seen a day before it broke up over Africa. Even a day's warning might be helpful for a bigger rock, but the longer the lead time, the better.

  • James Hoadley

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    Dec 1 2011: I've probably watched too many Bruce Willis movies, but would fracturing the asteroid do anything helpful?
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      Phil Plait

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      Dec 1 2011: Yes and no. If it's done way way way in advance it can help. What you don't want are lots of little piece headed toward us! But it you do break it up years in advance, then you have that many more pieces to keep track of which might hit us later. Best to keep it in one piece and move it all at once to a safe orbit.

  • Ted Judah

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    Dec 1 2011: There has been ideas of putting a transmitter on Apophis in order to most accurately track it' s orbit and definitively determine it's threat to us. What do you think such a mission would cost and would people support it? What about a global effort?
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      Phil Plait

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      Dec 1 2011: I love this idea, actually! We'd learn a lot about asteroids, and it would teach us how better to track them. A tracking device wouldn't be the only goal of such a mission, of course; we'd also be able to map out the surface, learn about the mineralogy of it, and many other interesting and important scientific questions. So the cost would be about the same as any other asteroid mission - hundreds of millions of dollars - but in real terms that's a small amount compared to, say, what Americans spend on cigarettes or pet food or cosmetics every year. And in this case, we might save the world!

  • Vanessa Luna

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    Dec 1 2011: What other applications could there be for the ion drive besides pulling an asteroid out of the way? For example, could it ever be a viable option for space travel?
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      Phil Plait

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      Dec 1 2011: Yes! In fact, ion drives have been used twice in spacecraft successfully, including the current Dawn mission which is orbiting the asteroid Vesta. Ion drives are very efficient. Even though they accelerate a rocket very slowly, they do so over long periods of time, and can actually get a probe moving *faster* than a chemical rocket can, if you don't mind waiting longer.
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    Andrew Macdonald

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    Dec 1 2011: What would the minimum size of an asteroid need to be to be life endangering on a mass scale? I heard there was one that passed within the Earth's orbit recently that was around the size of a plane - but surely this isn't big enough to effect life in general? Thanks for your time!
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      Phil Plait

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      Dec 1 2011: Global effects don't come in unless the impactor is pretty big; hundreds of meters across. But even one 30 meters across is big enough to make a crater a kilometer across, which would be bad. Astronomers want to be able to find all the ones bigger than 140 meters across: big enough to do significant damage, but not too small to find easily. Smaller ones are tough to find, bigger ones are easier. it seems like a fair compromise. Eventually, we want to find *all* of them, but for now we need reasonable goals.

  • Alexzander Samuelsson

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    Dec 1 2011: Hello Phil. Big fan of your blog and outreach.
    I have a question about the Levy-Shoemaker asteroid that struck Jupiter. Is there enough information about the trajectory of that asteroid to project it's path and see if it would have been a danger to Earth?
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      Phil Plait

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      Dec 1 2011: I think SL9 was in orbit around Jupiter, so there was never a danger of it hitting us. But it was just one of thousands of random comets out there! So we need to keep our eyes open to watch for any others. We get passed by comets all the time, and they are very, very rarely a danger to us. Still, the point it to be aware of them.

  • Bill VonTobel

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    Dec 1 2011: I'm not sure if this can really be answered...but what about society's reaction to an impending asteroid? A lot of people don't trust science as is, and wouldn't believe we could be saved. I would imagine that a massive education campaign would have to be in place to calm people down.
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      Phil Plait

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      Dec 1 2011: Good point. I think a lot of people would deny the problem, but I would hope enough would take it seriously to force action. I don't know what the reaction would be if we saw something coming and had like two years before impact! I don't know if much could be done outside of just hitting it with a space probe and hoping that's enough to move it out of the way. So the reaction of people here on the Earth with lots of lead time is not something I'm sure i can predict.

  • Steven Christenson

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    Dec 1 2011: The interface confuses me: "This conversation will close in 52 minutes, on December 1, 2011 at 11:00:00 AM" and "This Conversation will open on December 1st, 1 pm EST". No links to listen/join. Perhaps I'm just not TED material? :-(

  • Martin Walshe

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    Dec 1 2011: Hi Phil,

    If we happened to wake up in the morning to discover an asteroid of (suitably scary size) on a collision course with Earth how prepared would we be technologically to correct its course and how much warning would we require to put a plan into place (given unlimited money and government cooperation?
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      Phil Plait

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      Dec 1 2011: In reality, the longer the better! But we currently do NOT have a rocket and probe ready to go to prevent such a thing. It would probably take a few years to put a mission together, and then a few more at least for it to properly move the rock. The good news is, statistically speaking, we have time.It may be years before such a threat turns up. But I'd like for us to be ready when it occurs.

      • Martin Walshe

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        Dec 1 2011: Thanks for the answer Phil. Keep up the good work on making people aware :)

  • Rob K

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    Dec 1 2011: Not really about asteroids, but what would it take to build a space elevator? Can it be built in our life time and is it really a political decision rather than engineering one? Oh, and is it in danger of asteroids or space debris (do they count as asteroids?)? :D

    [Edit]
    Oh yeah, awesome twitter feed! Is it possible to tell what stars will give off GRB? Are there any in the neighborhood?
    [/Edit]

    • Ted Judah

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      Dec 1 2011: I believe the space elevator relies on the manufacture of a strong carbon ribbon with a particular nano-structure. The longest we have achieved so far is mere inches and we will need thousands of miles worth.
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      Phil Plait

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      Dec 1 2011: We'd need a very unreasonably strong material to make a space elevator, though carbon nanotubes are often talked about this way. My problem with space elevators is protecting them: a single meteor impact on one could destroy it, and then you have BIG problems. The engineering is interesting and maybe possible, and certainly the physics is well understood. But I bet the logistics would prove very difficult.
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